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Updates to Directory Interchange Format (DIF) Standard

Summary

This document describes modifications to the Directory Interchange Format (DIF) according to International Directory Network (IDN) Version 9.8.2 Release Notes, October 2010. NASA's Global Change Master Directory (GCMD) is an implementation of the DIF.

NASA Earth Science Community Recommendations for Use

Strengths

ESDS-RFC-023 documents recent changes to the DIF schema, intended to enhance interoperability with the Federal Geographic Data Committee (FGDC) Content Standard for Digital Geospatial Metadata (CSDGM) and the International Organisation for Standardisation (ISO) 19115 metadata standards. The DIF itself is already a NASA-endorsed metadata standard (ESDS-RFC-012). Earth Science community comments were all positive. Said one, "This RFC will clearly help integrating data management systems and should be endorsed."

Weaknesses

One commenter notes a perceived weakness: “It looks like, in this community, the separation of purpose out of an abstract is standard. But in normal usage, abstract may likely include purpose.” However, the separate abstract and purpose fields were created specifically to conform to FGDC and ISO metadata specifications.

Applicability

As NASA Earth Science Data Systems (ESDS) move toward adopting ISO metadata standards, closer alignment of our existing metadata standards is welcome. In the words of another commenter, “There will never be only one way of addressing the interoperability issue and DIF has a clear advantage in that it is lightweight and easy to implement and benefit from contrary to ISO standards.”

Limitations

Additional DIF schema changes, beyond the two documented here, will be needed for full ISO compatibility.

Overall, reviewers were pleased with the updates to the DIF schema, and found that the RFC documentation was clear and helpful: “For these minor changes an endorsement is a no-brainer.”